An open surgical repair of the injured medial patellar stabilizers, including the vastus medialis obliquus muscle and the medial patellofemoral ligament, after acute patellar dislocation was studied in eight patients. At initial examination, all patients had tenderness over the adductor tubercle and a positive patellar apprehension sign. Four of eight patients had obvious ecchymosis over the adductor tubercle. Magnetic resonance imaging, diagnostic arthroscopy, and open surgical exploration documented injury to both the medial patellofemoral ligament and the origin of the vastus medialis obliquus muscle. In all patients, the torn muscle was retracted in an anterior and superior direction and an arthroscopic lateral release was performed followed by open primary repair of the medial patellofemoral ligament to the adductor tubercle and repair of the vastus medialis obliquus muscle to the adductor magnus tendon. Patients were evaluated postoperatively with the Kujala scoring questionnaire. The average follow-up was 3.0 years, with a minimum of 1.5 years. No patients experienced a recurrent dislocation. The average Kujala score was 91.9. Patients rated their return to athletic activity at an average 86% of their pre-injury level. The average subjective satisfaction was 96%. In appropriate cases of acute patellar dislocation, we recommend primary repair of the medial patellofemoral ligament and the vastus medialis obliquus muscle to avoid recurrent dislocation, chronic subluxation, pain, and disability.
The purpose of this study was to evaluate the natural history of glenohumeral dislocation in young athletes. A review of the literature revealed a consensus of opinion that the dislocated shoulder should be immobilized from 3-6 weeks. However, a high recurrence rate could be expected. One hundred twenty-one patients with acute traumatic anterior dislocations were evaluated (average age-19 years). Methods of immobilization were shoulder immobilizers and slings and swaths. Sixty-two patients were immobilized and 56 (90%) of these suffered recurrent dislocation. Fifty-nine patients were not immobilized and 50 (85%) re-dislocated their shoulders. The length of immobilization had no effect on the recurrence rate. All re-dislocations occurred within 18 months of the initial injury. Seventy-nine patients were operated on for recurrent dislocation. With such a high recurrence rate in the athletic age group, the authors question if immobilization affects the prognosis.
Many clinical studies have emphasized the role of the hamstrings and the iliotibial band on knee mechanics, although few biomechanical studies have investigated it. This study therefore examined two hypotheses: (a) with loading of the hamstrings, the tibia translates posteriorly and rotates externally and the tibial contact pattern shifts anteriorly; furthermore, the changes in tibial kinematics alter patellar kinematics and contact; and (b) loading the iliotibial band alters the kinematics and contact pattern of the tibiofemoral joint similarly to loading the hamstrings, and loading the iliotibial band laterally translates the patella and its contact location. Five cadaveric knee specimens were tested with a specially designed knee-joint testing machine in an open-chain configuration. At various flexion angles, the knees were tested always with a quadriceps force but with and without a hamstrings force and with and without an iliotibial band force. The results support the first hypothesis. Hence, the hamstrings may be important anterior and rotational stabilizers of the tibia, a role similar to that of the anterior cruciate ligament. The results also support the second hypothesis, although the iliotibial band force had a smaller effect on the tibia than did the hamstrings force. Both forces also changed patellar kinematics and contact, demonstrating that these structures should also be considered during the clinical management of patellar disorders.
Rehabilitation of the symptomatic patellofemoral joint aims to strengthen the quadriceps muscles while limiting stresses on the articular cartilage. Some investigators have advocated closed kinetic chain exercises, such as squats, because open kinetic chain exercises, such as leg extensions, have been suspected of placing supraphysiologic stresses on patellofemoral cartilage. We performed computer simulations on geometric data from five cadaveric knees to compare three types of open kinetic chain leg extension exercises (no external load on the ankle, 25-N ankle load, and 100-N ankle load) with closed kinetic chain knee-bend exercises in the range of 20 degrees to 90 degrees of flexion. The exercises were compared in terms of the quadriceps muscle forces, patellofemoral joint contact forces and stresses, and "benefit indices" (the ratio of the quadriceps muscle force to the contact stress). The study revealed that, throughout the entire flexion range, the open kinetic chain stresses were not supraphysiologic nor significantly higher than the closed kinetic chain exercise stresses. These findings are important for patients who have undergone an operation and may feel too unstable on their feet to do closed chain kinetic chain exercises. Open kinetic chain exercises at low flexion angles are also recommended for patients whose proximal patellar lesions preclude loading the patellofemoral joint in deeper flexion.
By means of immunohistochemical staining, cells actively infected with human herpesvirus 6 (HHV-6) were found in central nervous system tissues from 8 (73%) of 11 patients with definite multiple sclerosis (MS). Interestingly, 17 (90%) of 19 tissue sections showing active demyelination were positive for HHV-6-infected cells compared with only 3 (13%) of 23 tissue sections free of active disease (P<.0001). Central nervous system tissues from 2 of 28 normal persons and patients with other inflammatory demyelinative diseases were positive for HHV-6-infected cells (P<.0001), and the 2 positive cases were diagnosed as having HHV-6 leukoencephalitis. By use of a rapid culture assay, blood samples from 22 (54%) of 41 patients with definite MS were found to contain active HHV-6 infections, compared with 0 of 61 normal controls (P<.0001). No significant difference was found between HHV-6 viremia-positive and HHV-6 viremia-negative MS patients with respect to type of disease (relapsing/remitting or progressive). In contrast, patients with active HHV-6 viremia were significantly younger and had shorter durations of disease than did HHV-6 viremia-negative patients.
Encephalitis lethargica (EL) was a complex and mysterious disease that appeared around the same time as the great influenza pandemic of 1918. The contemporaneous relationship of the 2 diseases led to speculation that they were causally related. Contemporary and subsequent observers conjectured that the influenza virus, directly responsible for the deaths of more than 20 million people, might also have been the cause of EL. A review of the extensive literature by observers of the EL epidemic suggests that most contemporary clinicians, epidemiologists, and pathologists rejected the theory that the 1918 influenza virus was directly responsible for EL. Disappearance of the acute form of EL during the 1920s has precluded direct study of this entity. However, modern molecular biology techniques have made it possible to examine archival tissue samples from victims of the 1918 pandemic in order to detect and study the genetic structure of the killer virus. Similarly, tissue samples from EL victims can now be examined for evidence of infection by the 1918 influenza virus.
This technique can be useful for in vivo clinical evaluation of cartilage thinning in the osteoarthritic patellofemoral joint.
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